Quote:Smart Reply is a feature on Gmail that uses algorithms and machine learning to suggest replies to emails to users of the service. The main idea behind it is to speed up the time it takes to reply to an email by selecting one of the suggested answers so that you don't have to type it.
The feature is available on desktop and mobile versions of Gmail. Suggested replies are short, e.g. "working on it", "Let's do Monday", or "Thanks a lot", and if you have contacts on Gmail that make use of the feature quite a bit, you may have received short auto-generated answers regularly already.
There are two main points of criticism when it comes to Smart Reply. The first is that the answers that it provides are short so that you won't save an awful lot of time when you use the feature. You may need to add more text to the message in many cases so that Smart Reply does not speed things up too much in most cases.
The second issue is one of privacy. To provide answers, Google's algorithms need to scan the email to decipher topics and generate replies based on what is being discussed. Google stopped scanning emails for advertisement purposes in 2017 but algorithms like Smart Reply rely on the content of the email to provide suggestions.
The feature returns suggestions for some email conversations only and not all conversations. It seems to work best for emails that include questions, e..g. "should we meet on Monday or Tuesday" but even those are not covered 100%.

Full reading: https://www.ghacks.net/2018/10/08/how-to-turn-off-gmails-smart-reply-feature/